This Bumpy Cake is a rich, nostalgic chocolate dessert featuring a moist chocolate base, thick rows of vanilla buttercream, and a smooth fudge icing that sets into a soft shell. Each slice delivers layers of creamy, cakey, and deeply chocolatey flavors, making it a truly unforgettable treat for any occasion.

Why You’ll Love This Recipe

This cake stands out because it’s more than just chocolate on chocolate. The piped buttercream creates soft pockets of vanilla sweetness under the fudge icing, giving every bite a satisfying contrast of textures. It’s simple enough for home bakers yet impressive enough for celebrations, birthdays, or holidays. If you love classic desserts with a twist, this cake is guaranteed to win you over.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

For the chocolate cake:

• 1 3/4 cups all-purpose flour
• 1 1/2 teaspoons baking soda
• 1/2 teaspoon salt
• 3/4 cup unsweetened cocoa powder
• 1 3/4 cups granulated sugar
• 1 cup unsalted butter, softened
• 3 large eggs, at room temperature
• 2 teaspoons vanilla extract
• 1 cup buttermilk
• 1 cup hot water or hot coffee

For the vanilla buttercream:

• 1/2 cup unsalted butter, softened
• 1/4 cup vegetable shortening
• 3 cups powdered sugar, sifted
• 2 to 3 tablespoons heavy cream or milk
• 1 teaspoon vanilla extract
• Pinch of salt

For the fudge icing:

• 3/4 cup heavy cream
• 1 1/2 cups granulated sugar
• 6 tablespoons unsalted butter
• 6 tablespoons unsweetened cocoa powder
• Pinch of salt
• 1 teaspoon vanilla extract

Directions

Preheat the oven to 350°F (175°C) and grease a 9×13-inch baking pan.

In a medium bowl, whisk together the flour, baking soda, salt, and cocoa powder. Set aside.

In a large bowl, beat the butter and granulated sugar until light and fluffy, about 3 to 4 minutes. Add the eggs one at a time, mixing well after each addition, then mix in the vanilla extract.

Add the dry ingredients to the butter mixture alternately with the buttermilk, beginning and ending with the dry ingredients. Stir in the hot water or coffee until the batter is smooth. The batter will be thin.

Pour the batter into the prepared pan and bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely in the pan.

To make the buttercream, beat the butter and vegetable shortening until smooth and creamy. Gradually add the powdered sugar, then mix in the vanilla extract, salt, and enough cream to achieve a thick, pipeable consistency.

Transfer the buttercream to a piping bag fitted with a large round tip. Pipe long, even rows across the cooled cake, leaving about 1 inch between each row. Chill the cake for 30 minutes.

For the fudge icing, combine the heavy cream, sugar, butter, cocoa powder, and salt in a saucepan over medium heat. Stir constantly until the mixture comes to a gentle boil and thickens slightly, about 4 to 5 minutes. Remove from heat and stir in the vanilla extract.

Let the icing cool slightly, then pour it evenly over the chilled cake, allowing it to flow over the buttercream bumps. Gently tilt the pan to spread the icing without using a spatula.

Chill the cake until the icing is set. Slice and serve.

Servings and timing

This recipe makes 15 generous servings.

Preparation time is about 30 minutes, baking time is 35 minutes, and chilling time is approximately 1 hour. Total time from start to finish is about 2 hours and 5 minutes.

Variations

For a deeper chocolate flavor, use hot coffee instead of hot water in the cake batter.
You can swap the vanilla buttercream for chocolate buttercream if you prefer an all-chocolate version.
Add a teaspoon of espresso powder to the fudge icing for a subtle mocha note.
For a lighter texture, reduce the buttercream rows slightly and space them farther apart.

Storage/Reheating

Store the cake in an airtight container at room temperature for up to 4 days or in the refrigerator for up to 7 days.
To freeze, wrap individual slices or the whole cake tightly in plastic wrap and then foil. Freeze for up to 3 months. Thaw in the refrigerator or at room temperature before serving. Reheating is not recommended, as it can soften the buttercream and icing too much.

FAQs

What makes Bumpy Cake different from regular chocolate cake?

The piped rows of buttercream under the fudge icing create creamy pockets that give the cake its signature texture and flavor.

Can I make this cake ahead of time?

Yes, it can be made a day in advance and stored in the refrigerator until ready to serve.

Do I need a piping bag for the buttercream?

A piping bag works best, but a zip-top bag with the corner snipped off will also work.

Can I use milk instead of buttermilk?

Yes, you can make a substitute by mixing 1 tablespoon of vinegar or lemon juice with 1 cup of milk and letting it sit for 5 minutes.

Is coffee necessary in the cake batter?

No, it’s optional, but it enhances the chocolate flavor without making the cake taste like coffee.

How do I get clean slices?

Use a sharp knife dipped in hot water and wiped dry between cuts.

Can I use Dutch-processed cocoa powder?

Natural cocoa powder is recommended for the best rise and classic flavor, but Dutch-processed can be used with slightly different results.

Will the fudge icing harden completely?

It sets into a soft, sliceable shell rather than becoming hard.

Can this cake be made in a different pan?

A 9×13-inch pan works best, but you can use two 9-inch round pans with adjusted baking time.

Is this cake suitable for celebrations?

Absolutely, it’s a popular choice for birthdays and special gatherings because it serves many people and looks impressive.

Conclusion

Bumpy Cake is a timeless dessert that combines rich chocolate cake, creamy vanilla buttercream, and smooth fudge icing into one indulgent treat. With its unique texture and nostalgic charm, it’s a recipe worth adding to your baking rotation, whether you’re celebrating a milestone or simply craving a truly special chocolate cake.

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